Coal tars and pentachlorophenol solutions have contaminated a large number of industrial sites in the United States. Coal tars have been produced at over 1500 manufactured gas facilites (cf. Anastos et al., Second Conference on Management of Municipal, Hazardous, and Coal Wastes Proceedings, Morgantown, W. Va., 1984; Unites and Housman, 5th Annual Madison Conference of Applied Research and Practice on Municipal and Industrial Waste Proceedings, University of Wisconsin, Madison, Wis., 1982; Krumrine, 1983 Technical Report 83-59T, Lafayette Hill, Pa.; Pereira et al., Env. Tox. and Chem. 2: 283-294, 1983; and U.S. EPA, "Survey of Town Gas and By-product Production and Locations in the U.S." (1880-1950), 1985) and at numerous coking plants for the steel industry (cf. Coates et al., Mech. Eng. 104 (2): 42-51, 1982). Creosote derived from coal tar and pentachlorophenol mixed with diesel oil have used as preservatives at over 1000 wood treating plants (cf. Hickok et al., ASCE Environmental Engineering Division Specialty Conference Proceedings, 1982). In many cases, these dense organic liquids have leaked from waste treatment facilites or have been injected into disposal wells. About 40 wood treating sites are already included on the National Priorities List.
Discharges of dense oily liquids typically result in saturated subsurface accumulations of oily wastes (cf. Villaume, Groundwater Monitoring Review, Spring, 1985, 60-74). When they are denser than water, oily waste discharges permeate downwardly through the subsurface until further penetration is blocked by natural impermeable barriers such as bedrock or clay. Above these barriers, the organic liquid phase accumulates by filling a large fraction of the subsurface pore space. When the pore space becomes saturated with organic liquids, the oily waste accumulation spreads along the impermeable barriers. If this spreading accumulation encounters fractures, discontinuities or more permeable sections in the barriers, then the oily wastes penetrate into deeper strata.
Saturated subsurface accumulations of oily wastes are a persistent source of groundwater contamination. High organic liquid saturations reduce the relative permeability to water, so groundwater does not readily permeate oily waste accumulations. This natural resistance to groundwater permeation is expected to retard extraction of water-soluble compounds. Contaminants such as pentachlorophenol and polynuclear aromatic hydrocarbons have water solubilities less than 20-30 ppm (Goerlitz et al., Environ. Sci. Technol. 19(10): 955-961, 1985; Rao, editor, "Pentachlorophenol: Chemistry, Pharmacology, and Environmental Toxicology", Plenum Press, New York, 1978). At the expected high initial concentrations of these compounds, even an effective groundwater permeation would take decades to extract all of these contaminants.
High organic liquid saturations hinder natural microbial degradation of oily waste accumulations. Some of the organic liquid components are toxic to groundwater bacteria, and higher concentration of these compounds are expected when groundwater dilution is reduced by a low relative permeability to water. A low rate of groundwater permeation also reduces the supply of nutrients for microbial activity. These conditions are expected to limit the rate of either natural or induced microbial degradation and may even isolate large areas of oily waste accumulations as sterile environments.
Conventional groundwater treatments primarily address only lateral transport of soluble contaminants from oily waste accumulations. Pump-and-treat methods and slurry walls do not stop downward penetration of dense organic liquids and do not appreciably improve conditions for microbial degradation. Therefore, these conventional groundwater treatments require long-term maintenance and monitoring. During this long period, treatment requirements may increase if oily waste accumulations permeate downward and contaminate deeper aquifers.
Excavation can recover only shallow accumulations of oily wastes. In this case, organic liquids are removed to the depth of the excavation, but the excavation and subsequent treatment costs are high, and the exposure of contaminated materials can produce vapor emissions. Excavation is not practical for recovering deep accumulations of oily wastes, especially when the organic liquids have penetrated bedrock barriers.
Waterflood and steamflood technologies have been used extensively for petroleum and heavy oil production. Laboratory experiments have tested different operating parameters for waterflood (cf. Craig et al. "Oil Recovery Performance of Pattern Gas and Water Injection Operations from Model Tests," Transacation of AIME, 204: 7-15, 1955; Rapoport et al. Transactions of AIME, 213: 113-120, 1958), hot-waterflood (Dietz "Hot Water Drive", 7th World Petroleum Congress Proceedings, Mexico City, Mexico, April, 1967; El-Saleh and Farouq Ali, Soc. Petr. Eng. Jour., 351-355, 1971), and steamflood processes (cf. Willman et al., Transactions of AIME 222: 681-690, 1961, Closmann et al., Soc. Petr. Eng. Jour. 417-426, 1983). Field applications of these processes have been reported by Bursell in J. Petro. Tech., 1225-1231, October, 1970, and Konopnicki et al., in J. Petro. Tech. 546-552, May, 1979. Chemical additives have also been tested in previous waterflood and steamflood studies.
Zwicky, in U.S. Pat. No. 3,527,303, discloses a steam soak for recovering crude oil wherein a producing formation is first heated with steam and then produced. Caustic or detergents may be added to the steam to increase the affinity of the formation rock for water.
Clingman, in U.S. Pat. No. 4,057,106, discloses a method for injecting heated water into a partially depleted oil deposit to effect recovery of residual oil contained therein.
Parks et al., in U.S. Pat. No. 3,096,777, disclose that the adhesion of solid hydrocarbonaceous substances on walls of production equipment for oil deposits can be inhibited by contacting the wall with an aqueous dispersion comprising a hydrophilic water-dispersible colloid-producing polymeric substance such as alkali metal salts or lignosulfuric acid, glues, gum arabic, and the like.
Craig, Jr., in U.S. Pat. No. Re 25,918, discloses a method for recovering heavy oils from underground strata by steam extraction.
Bergman, in U.S. Pat. No. 2,470,132, discloses a well washing fluid comprising water soluble salts of carboxyalkylcellulose ethers along with saline material. This composition can be used to prevent swelling or plugging by bentonites or clays in the wells.
Bansbach, in Canadian Pat. No. 1,059,744, discloses a method for removing paraffin from surfaces to which they adhere. The method comprises subjecting the plugged surfaces to the action of a hot aqueous solution of a surfactant which can remove paraffin. The preferred compounds are nonionic surfactants, preferably oxyalkylates.
Russian Pat. No. 1,162,947 discloses that thioalcohols having from 2 to 6 carbon atoms, and alkyl alcohols having from one to 3 carbon atoms, can be used as surfactants for removing tar, asphaltene, and paraffin deposits.